ABSTRACT

The history of storm spotting and public
awareness of the tornado threat is reviewed. It is shown that a
downward trend in fatalities apparently began after the famous
"Tri-State" tornado of 1925. Storm spotting's history begins in World
War II as an effort protect the nation's military installations, but
became a public service with the resumption of public tornado
forecasting, pioneered in 1948 by the Air Force's Fawbush and Miller
and begun in the public sector in 1952. The current spotter program,
known generally as SKYWARN, is a civilian-based volunteer
organization. Responsibility for spotter training has rested with the
national forecasting services (originally, the Weather Bureau and
now, the National Weather Service). That training has evolved with
(a) the proliferation of widespread film and (recently) video footage
of severe storms, (b) growth in the scientific knowledge about
tornadoes and tornadic storms, as well as a better understanding of
how tornadoes produce damage, and (c) the inception and growth of
scientific and hobbyist storm chasing.

The concept of an integrated warning system is
presented in detail, and considered in light of past and present
accomplishments and what needs to be done in the future to maintain
the downward trend in fatalities. As the integrated warning system
has evolved over its history, it has become clear that volunteer
spotters, and the public forecasting services need to be closely
tied. Further, public information dissemination is a major factor in
an integrated warning service; warnings and forecasts that do not
reach the users and produce appropriate responses are not very
valuable, even if they are accurate and timely. The history of the
integration has been somewhat checkered, but compelling evidence of
the overall efficacy of the watch/warning program can be found in the
maintenance of the downward trend in annual fatalities that began in
1925.

1. Introduction

Although meteorologists readily acknowledge that their forecast
products are not perfect, it is not always clear within the
meteorological community how important public awareness can be in
making forecasts successful in societal terms. It is natural that
meteorologists focus on the meteorological aspects of the severe
weather forecasting system; this is what meteorologists know best.
Nevertheless, it is becoming ever more clear that public awareness is
a major limiting factor in the success of severe weather forecasts,
especially the very short-range forecasts we call "warnings" for
severe convective weather events such as tornadoes. The users of
weather forecasting information must hear the forecasts, must
interpret them in their own terms in order to make decisions,
and must know what to do in order to achieve some desired
result, if the forecasts are to be successful in having a positive
societal impact.

For severe convective weather (hereafter referred to as "severe
weather") forecasts, most notably those associated with tornadoes,
the recipients of the various forecast products (outlooks, watches,
and warnings; see Ostby 1992) must accept some level of
responsibility for their own safety. Since the pioneering tornado
forecasting efforts of United States Air Force meteorologists Ernest
J. Fawbush and Robert C. Miller, the public has come to accept that
the National Weather Service (hereafter, NWS) will provide forecasts
and warnings to help the users to help themselves. Over time, the NWS
also has accepted the responsibility for training severe weather
spotters who volunteer to serve their communities by watching for
imminent severe weather events, again most notably tornadoes (but not
limited to tornadoes).[1]
Finally, the NWS produces public information materials and makes them
available for improving public knowledge of severe weather and what
to do about it. All of these NWS activities have evolved in an effort
to increase the likelihood that the forecast products will have the
desired result of reducing severe weather-related casualties and
damage.

As we review the history of the public awareness program since the
inception of tornado forecasting in the late 1940s, we want to
consider that history in a larger context. As shown in
Fig. 1, the trend of the annual
population-normalized death toll from tornadoes was nearly constant
during the end of the 19th century and well into the first three
decades of the 20th century, It appears that something different
began to happen after 1925. Although we can only speculate about the
reasons for this change in the population-adjusted fatality rate, it
seems likely that the deadly "Tri-State" tornado of 18 March 1925
made it clear to the nation that spreading the word about a
long-track tornado could have a positive impact on the populace in
the storm's path. Radio and telephone communications technology
proliferated during this decade, providing innovations that permitted
rapid dissemination of warnings based on ongoing tornado events.
Thus, it is possible that the Tri-State tornado initiated a trend
toward public awareness that, combined with new communications
technology, encouraged preparation for potentially disastrous
tornadoes that continues to this very day.

Fig. 1. Trends in the normalized annual tornado death toll, where
the normalization is by the population of the United States for that
year. The annual population has been estimated by linear
interpolation between the census figures (at 10-year intervals). The
raw data were smoothed (red solid line) by one pass of a three-point
median filter and one pass of a five-point simple moving average. The
solid dark green lines are the regression line fitted to the filtered
data for the period from 1880-1925 and for the period from 1925-1995;
the dashed lines are the 10th and 90th percentiles about the
regression line for the period 1925-1995. The regression equations
for each line are also shown.

It should be noted also that in the period from 1925 onward, there
was a nationwide population movement away from rural areas and into
cities (see López and Holle 1998). Thus, the population has
become more and more clustered into large cities and the rural
population, inherently more dispersed, has been declining. It is not
known to what extent this may have influenced the trend shown in Fig.
1, but this demographic trend has two counteracting potential
impacts. First, by clustering the population, it reduces the chances
of a population center being hit. Second, on the relatively rare
occasions when such a concentration of population is affected by a
tornado, it increases the potential for casualties.

The important innovations of Fawbush and Miller and all of the
subsequent public severe weather forecast product developments since
the first tornado forecasts of the modern era can therefore be seen
as contributions toward continuation of a trend that commenced more
than two decades earlier in the wake of the Tri-State catastrophe. We
will try to show that NWS efforts, past and present, to enhance
public awareness have maintained a trend toward an exponential
decrease in the normalized fatality rate. One of our goals will be to
provide documentation of the training and preparedness materials
created for the purpose of enhanced public awareness, as well as some
overdue recognition of individuals who contributed to these public
awareness efforts, and to the national program of volunteer storm
spotters. It also will be shown that the effect of public tornado
forecasting can be seen on the death tolls of major tornado events,
but that success in reducing casualties from severe convective
weather events cannot be used as an excuse to reduce the resources
devoted to the task.

2. History

a. Storm Spotting

As public awareness grew in the decades following the Tri-State
tornado, it developed in a context wherein no efforts were being made
to provide tornado forecasts. The earlier efforts of John Park Finley
(Galway 1985) in tornado forecasting came to an abrupt end in 1886
(Galway 1989) and were not pursued further. Even the word "tornado"
was banned from the Weather Bureau lexicon thereafter for many
decades. In 1938, the word "tornado" was again approved officially
for use with warnings, but not with forecasts (Bates 1962). With the
recognition during World War II that defense installations and war
production centers (like ammunition dumps and military supply depots)
were quite vulnerable to thunderstorms and tornadoes, it is not
surprising that the first efforts in organized spotting began in the
military.

During 1942 and 1943, the Weather Bureau cooperated with the
military in setting up volunteer storm spotter networks in various
places around the country where it was deemed important (Bates 1962;
Galway 1992). At first, the primary concern was for lightning near
ordnance plants, but the program grew substantially during the war
and the mission of the spotters expanded to include other hazardous
weather, including tornadoes. It is known that tornadoes had
significant impacts on war production plants on 27 April 1942 in
Pryor, Oklahoma (Grazulis 1993; p. 899), and damaged several
buildings, including a barracks, at Fort Riley, Kansas on 15 May 1943
(Grazulis 1993; p. 906). The year 1942 was notable for a substantial
number of significant tornado events and those may have been
influential in expanding the role of the military spotter networks.
Undocumented near-misses also might have contributed to the concerns
of military authorities for tornadoes during the war. Galway (1992;
see his Fig. 3) notes that by June of 1945, there were more than 200
observer networks in place around the country. The origins of
volunteer spotting probably predate this period, but the impetus for
widespread encouragement and use of storm spotting is apparently a
direct result of concerns on the part of the military during the war.

After World War II, the spotter networks were maintained, at least
in part because of the continuing importance of military
installations. After the catastrophic tornadoes of 9 April 1947 that
tracked across parts of three
states,[2] the state of
Texas began to put a special emphasis on volunteer spotters. A local
spotter network was considered crucial in the issuance of warnings
for a 1951 tornado near White Deer, Texas (Whitnah 1961; p. 216);
another volunteer spotter group was noted to have been vital in
triggering warnings during a tornado near Bryan, Texas, also in 1951
(Popkin 1967; p. 186). Following that, a major disaster at Waco,
Texas on 11 May 1953 stimulated the development of the Texas Radar
Tornado Warning Network (News and Notes 1955). Although radar was a
major component of this effort in Texas, wherein cities could buy
surplus radars from the Federal Government for the price of
installation and modification, the program also incorporated
volunteer storm spotters. Apparently, the surplus radars never became
a significant part of the system, but the spotters certainly did.

By the mid-1950s, spotters were well on their way to becoming
commonplace, at least within the tornado-prone parts of the United
States where terrain and visibilities permit them to be of
use.[3] This evolution
followed rather directly in the wake of the inception of public
tornado forecasts, permitting the alerting and deployment of spotters
in advance of threatening weather situations. It is well-known, of
course, that the first tornado forecasts were issued by the United
States Air Force forecasters Ernest C. Fawbush and Robert C. Miller
on 25 March 1948, from Tinker Air Force Base. By March of 1952, the
United States Weather Bureau had initiated its own public severe
storm forecasting service, known as the Severe Local Storms
Forecasting Unit (abbreviated as SELS; see Galway 1989; Corfidi 1999)
, first in Washington, D.C.; this forecasting group moved to Kansas
City, Missouri in August
1954.[4] Although SELS has
not taken a direct hand in recruiting spotters or even promoting
their use, its products permit the timely deployment of spotters.
Thus, it certainly can be said that public tornado watches have been
a major impetus to the spotting program; it is also apparent that the
deployment of spotters promotes the detection of tornadoes. The
record of the number of tornadoes observed
(Fig. 2) shows clearly the impact of the
proliferation of spotter programs in the era following the formation
of SELS (see Galway 1992).

Fig. 2.
Annual number of tornadoes for the period 1916-1995; the dashed line
connecting solid circles shows the raw data, the red heavy solid line
is the result of smoothing (using the same method as described in
Fig. 1 caption). Also shown in the green light solid line is the
number of tornado days (i.e., days with one or more tornadoes) per
year.

Another watershed event was the Palm Sunday outbreak of
tornadoes of 11 April 1965. Although the SELS tornado watches were
reasonably accurate for that event and there were at least some local
warnings (often with the help of volunteer spotters), the findings of
the Weather Bureau Survey Team (1965) led by Paul H.
Kutschenreuter[5] made it
quite clear that the dissemination of the meteorological information
was less than adequate and that the public was poorly prepared to use
the information if and when they received it. Among other things,
this led to the formation of the Natural Disaster Warning system
(NADWARN) to coordinate the various Federal agencies (the
participating agencies and their names have changed regularly) that
have natural disaster-related emergency functions. NADWARN soon
included a tornado-specific plan that we know now as SKYWARN. Also in
association with the post-Palm Sunday era, the tornado "forecasts"
officially became tornado "watches" in 1966 (Galway 1989).

With the development of SKYWARN, the spotters have had a structure
within which they operate in collaboration with the NWS. It is beyond
the scope of this review to evaluate the effectiveness of the program
as a whole, but the overall efforts have been important in the
reduction of fatalities from major tornadoes. For example, no single
tornado since 1953 has resulted in 100 or more fatalities; the last
such event was the Flint, MI tornado of 8 June 1953, that killed 114
people. Note that communications technology, notably telephone and
radio, has been an important component of the spotter network.
Spotters have to get their information to their communities; we'll
have more on this aspect of the program in section 3.

b. Spotter training programs

It was recognized early on that if volunteers are to provide
useful information about approaching storms to their communities (and
through the local emergency managers to the NWS), the spotters need
training. The Weather Bureau (now known as the NWS) readily accepted
a key role in the development of such training materials and has
always been ready to provide such training when asked. The history of
these training materials has not been well-documented in the past.
Many individuals, in and out of government, have contributed to the
creation of training films/videos, slide programs, and pamphlets and
especially with respect to the earliest of these, in the 1950s and
1960s, we have relatively little information about who was involved.
Apparently, the labors associated with producing these in the era
from the late 1950s to the early 1970s were considered simply part of
someone's job and relatively few of those involved have ever received
any public recognition, unfortunately.

The following represents an abbreviated review of the materials
that have been produced for spotter program training. We cannot claim
this list to be complete or exhaustive, but it does provide some
sense of the timing and content of spotter-related training material.
The listings also identify, to the best of our current ability, those
who have contributed, in an effort to provide individual credit where
it is due. We begin with spotter training films and videos; we may
have missed some examples. We find that most of the information from
the late 1950s through the early 1970s about who was responsible for
the development of these films is not readily available.

1. "Tornado" (1956) -- a "Calvin Production"
sponsored by United Gas Corp. and Texas Eastern Transmission Corp.,
set in the fictitious town of Elmville, OK. It showed a volunteer
spotter who phones in a tornado report to the local Weather Bureau
office. News and Notes (1957; p. 300) points out that the sponsors of
this film received a Public Service Citation from the Weather Bureau,
and that Berne P. Hughes (then the Meteorologist in Charge at
Shreveport, LA) is "cited for his excellent technical assistance
during the development and production of the tornado film," receiving
a Superior Accomplishment Award. Mr. Hughes also is noted as being
responsible for presenting the idea for the film to the eventual
sponsors. The Bulletin of the American Meteorological Society
(1957; p. 411) notes later that Harry E. Altman also received a
Superior Accomplishment Award "in recognition of his work leading to
the production" of the film.

2. "Tornado!" (1968) -- produced for the Weather Bureau by
Astra Films Inc., with Jeff Baker noted as the executive producer,
Leonard Grossman noted as the producer, and including Northern
Natural Gas Corp. among those acknowledged. It made the distinction
between watches (for planning) and warnings (for action). It
premiered at the Smithsonian Museum in January of 1968. As of this
writing, we have no information about any individuals who may have
made important contributions during the production of this film.

3. "Twister" (1972) -- produced by the NWS in cooperation
with the Defense Civil Preparedness Agency (hereafter, DCPA). It
focused on the 11 May 1970 Lubbock, Texas tornado disaster. As of
this writing, we have no information about any individuals who may
have made important contributions during the production of this film.

4. "Day of the Killer Tornadoes" (ca. 1975) -- produced
mostly by the DCPA, highlighting the 3-4 April 1974 "Super Outbreak,"
depicting honestly the local situations in Brandenburg, Kentucky;
Xenia, Ohio; Cincinnati, Ohio; Louisville, Kentucky; and Huntsville,
Alabama. The first two had little preparedness and no sirens, the
last three had excellent disaster plans and sirens, and the film
points out the differences in community death tolls. As of this
writing, we have no information about any individuals who may have
made important contributions during the production of this film.

5. "Neosho" (ca. 1976) -- produced by the NWS (with
significant support, including assistance with the funding, from Herb
Lieb) provided an example of what could be done by communities. It
focused on the 24 April 1975 tornado in Neosho, Missouri. The DCPA
may have been involved, as well. As of this writing, we have no more
information about individuals or groups who may have made important
contributions during the production of this film.

6. "Tornado - A Spotter's Guide" (1977) -- produced by Mike
and Betty Durham and Dan Purcell for the NWS, with input from Les
Lemon, Chuck Doswell and Al Moller. This film was produced to update
storm spotting, based on what storm intercept efforts had learned
since 1972; it also was the basis for developing a new spotter
training slide series (see below). It featured an emphasis on what
storms look like before they produce tornadoes, noting the
significance of the rotating wall cloud. It became the top-selling
U.S. Government film ever in peacetime.

7. "Terrible Tuesday" (1984) -- produced by the NWS,
focusing on the 10 April 1979 major tornado event in Wichita Falls,
Texas. It emphasized the importance of preparedness, spotter
training, etc. As of this writing, we have no information about any
individuals who may have made important contributions during the
production of this film.

8. "Stormwatch" (1995) -- co-produced for the NWS by Martin
Lisius of Prairie Pictures, Inc., Al Moller, and Gary Woodall. This
represents an advanced spotter training video, providing more
advanced aspects of storm structure and emphasizing the differences
between wall clouds that are likely to become tornadic vs. those that
are not.

The various Weather Bureau/NWS slide sets, pamphlets, and
brochures for spotter training are revised at irregular intervals.
The budget for these items is quite modest and subject to reduction
in times of fiscal distress. Most recent revisions have been done on
quite small budgets and with very limited financial resources; a lot
of time and effort has been contributed without charge by concerned
individuals both in and out of government. As with the films and
videos, we make no pretense of having a comprehensive listing here,
but the following list is at least broadly representative. As of this
writing, we are mostly unaware of by whom and under what auspices
training brochures and manuals were created prior to the mid-1970s.

1. "Severe Storm Reporting Handbook"(1956) -- This
document provided information about how to go about reporting severe
weather, including tornadoes, to the "collection agency" associated
with a volunteer observing network. It described how to recognize a
tornado and included a few photographs, and even some safety rules.

2. "It looks like a Tornado" (1959) -- This document
(Fig. 3) stated that it is an "Official
Weather Bureau handbook for use by tornado network observers" and
included photographs of tornado look-alikes, as well as variations on
tornadoes.

3. "Severe Local Storms - Spotter Training Slide
Lecture Series" (1969) -- This program apparently was produced by
Weather Service Headquarters in response to requests from field
offices for updates to the Storm Reporting Handbook.

4. "Spotter's Guide for Identifying and Reporting Severe Local
Storms" (1970) -- A pamphlet that provided: meteorological
information about hazards associated with thunderstorms, information
about tornadoes in particular, an example of the life cycle of a
tornado (near Freeman, South Dakota on 1 June 1965; an example much
used in later revisions of tornado pamphlets of all sorts), tornado
look-alikes, and reporting procedures.

6. "The Safest Place in Schools" (1976) -- a slide program
developed by Prof. James Abernathy of the Lawrence Institute of
Technology in Southfield, Michigan. This program was prepared after
several schools were struck during the 3-4 April 1974 tornado
outbreak.

7. "Tornado Safety in Residences" (ca 1978) -- another
slide program developed by Prof. Abernathy.

8. "A Slide Series Supplement to Tornado - A Spotter's
Guide"Slide Set (1978) --
Designed to accompany the film "Tornado - A Spotter's Guide" during
spotter training sessions, this program was the first revision of the
spotter training material based on storm chasing experiences. Les
Lemon was the leader in development of this set, which provides
comprehensive storm structure information for spotters for the first
time. Chuck Doswell developed most of the schematics used in the
series, provided input, and contributed images for use in the series.
Al Moller also provided input and images; many storm chasers, notably
including David Hoadley, contributed images for use in this slide
program.

9. "Spotter's Guide"(1981) -- A pamphlet
created as a revision to the earlier pamphlet, as an additional
supplement to the film "Tornado - A Spotter's Guide." This
incorporated the new information about storm spotting that began with
the 1979 film, providing some of the same schematic storm structure
diagrams developed for the slide series. It also showed sequences of
tornadoes starting from before the tornado and illustrating wall
cloud formation, provided examples of tornado look-alikes, gave
information about spotting procedures, and presented a glossary of
storm-related terminology. Larry Mooney was instrumental in producing
this document, with input from Al Moller and Chuck Doswell.

10. "A Look at Thunderstorms and their Severe Weather
Potential" (1988) -- Subtitled "An Advanced Severe
Storm Spotter Training Slide Series," leader of this program was Al
Moller, who also contributed images and guided the content, with
input (including designing new schematics) and images from Chuck
Doswell, and with photo contributions from several other storm
chasers. NWS Southern Region Headquarters provided considerable
support for the development of the series. Joan Kimpel of the
National Severe Storms Laboratory created the finalized graphics, and
a presentation of the concept of the series (Moller and Doswell 1988)
won the "Best Graphics" award at the 1988 American Meteorological
Society's 15th Conference on Severe Local Storms held in Baltimore,
Maryland.

12. "Concepts of Severe Storm Spotting"(1996) -- Subtitled "A Basic/Intermediate Spotter Training
Program," this was developed primarily by Gary Woodall, with input
from Al Moller and Greg Stumpf, and benefited from production
assistance contributed by Bill Alexander and Linda Kremkau in NWS
Headquarters. As is the norm now, many storm chasers contributed
images for this slide program. This was an update of the earlier
basic spotter training slide set introduced in 1978.

c. Public awareness programs

The following materials (films, pamphlets, etc.) are aimed at the
public, rather than spotters, attempting to raise public awareness of
tornadoes and what to do in case people experience threatening
weather situations. It has become clear that as the meteorological
science and wind-engineering knowledge associated with severe local
storms (especially, tornadoes) grows, topics that we thought we
understood are revised and so our recommendations about actions have
to change. Public education efforts are a major task, and having to
"unteach" something can be frustrating and is almost never 100%
effective. Making changes to the safety rules, for example, has
proven to be maddeningly difficult. Myths about tornadoes survive,
including myths that once were ideas on the frontiers of our science
[see, e.g., Reynolds (1958)]. That is, the changing science turns our
apparently scientific facts into mythology as we learn more. There
doesn't seem to be any way around the fact that our science is going
to change and that we thereby will be forced to change the messages
we give to the public. However, this probably argues for a moderately
conservative viewpoint regarding changes to our public pamphlets and
other materials.

As we have noted, public awareness appears to have been a major
factor in the exponential decrease in per capita tornado fatality
rates. Although the NWS has been reasonably conscientious in
developing revised tornado spotting training as new things are
learned, it perhaps can be said that we are much less involved in
developing programs aimed at educating the public at large about our
changing science of severe local storms than we are in developing new
spotter training materials. Given that public awareness appears to
have been a major factor, if not the major factor, in
declining tornado death tolls, it seems inappropriate not to be
putting a significant emphasis on this aspect of an integrated
warning system. What follows is a short history of documents intended
for public use.

1. "Tornadoes - what they are and what to do about
them" (1960) -- This was a short (4-page) NWS pamphlet giving
some brief summaries of climatological and meteorological information
that was apparently aimed at the public.

2. "Tornado Watch" (1965) -- This small NWS pamphlet
described what a tornado watch is and uses as an example the watches
issued for the Palm Sunday outbreak of 11 April 1965.

3. "Tornadoes" (1965) -- This was a series of pamphlets
from the NWS that provided summaries of climatological and
meteorological information about tornadoes for the public, including
tornado safety information, preparedness planning, and information
about other thunderstorm-related hazards. It was issued annually,
often with "facelifts" of various sorts, including being re-named
"Tornado" by 1967. In its 1965 and 1966 incarnations, it even
provided instructions for building a personal "tornado cellar." The
1970 version (Fig. 4) featured the
Tracy, MN killer tornado of 13 June 1968 (rated an F5) on its cover.

Fig. 4. Cover of the 1970 National
Weather Service pamphlet entitled "Tornado".

4. "Tornado - Approaching the Unapproachable"
(1972) -- produced by Tom Grazulis of Environmental Films, Inc.
This film showed several clips of tornadoes, including the infamous 2
April 1957 event in Dallas, Texas. It was quite popular, having been
shown on television many times.

6. "Tornadoes ... Nature's Most Violent Storms" (1992) --
This was an updated version of earlier public information pamphlets,
produced by a collaboration among the NWS, the Federal Emergency
Management Agency, and the American Red Cross. It is one of a
pamphlet series that covers other hazardous weather events (e.g.,
floods, winter storms, hurricanes, etc.) besides tornadoes. Notable
among the items within this pamphlet are some "tornado myths" that
include an attempt to change the safety rule about opening windows to
alleviate pressure drops associated with the tornado that at one time
were believed important in causing buildings to "explode." As with
other, older tornado safety rules, this one has been known for some
time to be erroneous and possibly dangerous.

3. An integrated warning system

Spotters are just one component of an integrated warning system.
An integrated warning system (hereafter, IWS) consists of the four
basic elements: forecast, detection,
dissemination, and public response (Leik et al. 1981). As
noted in Moller et al. (1993), there are three primary groups of
users of weather information in an IWS: 1) news media and private
sector meteorologists, 2) emergency management officials and storm
spotters, and 3) the general public. The latter group, the general
public, is difficult to characterize in terms of its needs and
interests, since "the public" is not a monolithic group with a single
set of requirements. Perhaps the first two groups are not homogeneous
either, but there certainly are some common threads within them.

It already has been noted that even if meteorologists could
produce forecasts that are perfectly precise and accurate, when the
other parts of the IWS break down for some reason, those forecasts do
not achieve fully their purpose of reducing casualties and damage
(see Perry and Mushkatel 1984; Chap. 2). The historical information
we have provided makes it quite clear that public awareness and
preparation can make a large difference in the outcome of a given
meteorological event.

The NWS has direct contact with the public only through the
somewhat limited medium of the NOAA Weather Radio (see below); the
majority of its information concerning hazardous weather reaches the
users of that information by means of the media, private sector
meteorologists, and emergency managers. Although this arrangement
works reasonably well across the nation, there are a few places where
the relationship among the groups has not always been as cordial and
mutually supportive as it needs to be. Moreover, the various
disseminators of weather information are not always on the best of
terms with each other. Competition for market share can become a
negative factor within an IWS. Even emergency managers (hereafter,
EMs) and spotter groups within a community can at times be troubled
by internal problems that can interfere with effective dissemination
of weather information to the users. However, we want to emphasize
that most of the time and in most locations, the arrangement operates
satisfactorily because all the participants are supportive of a true
integration of the components. A truly integrated warning results
whenever and wherever the local participants choose to suppress their
internal conflicts (if any) for the greater good of public service.

The NWS has certain key roles (forecasts and warnings,
meteorological aspects of storm spotter training), but the vital jobs
of dissemination and community protection are in the hands of the
media and the EMs. Let us review briefly how things would work in an
ideal world.

The IWS process actually can be said to begin well before any
severe weather has even begun to loom on the horizon. Local
communities, including the citizens as well as public officials
within them, have to accept a primary responsibility for preparing
their communities to deal with what is a relatively rare phenomenon.
The tasks associated with this responsibility include: development
and implementation of a disaster emergency plan, initiation of
contact with the NWS and other agencies of Federal and state
government to coordinate the planning and spotter training sessions,
and the identification of participants in a storm spotting network.
There must be some sort of Emergency Operations Center (hereafter,
EOC) set up that can coordinate all aspects of the program within
that local community during an event, including communication with
the NWS, other disaster agencies, and within the local community.

From that point, the NWS is invited to put on storm spotter
training programs at the request of the local
EMs.[6] The needs of the
communities can vary, depending on the experience level of their
spotters. The offering of advanced spotter programs, beyond the basic
material presented to new spotters, is contingent on the experience
level of the local spotters. Some programs have very enthusiastic and
innovative leaders, who can broaden the range of speakers available
by bringing in outside expertise to supplement the training provided
by the local NWS. Nevertheless, the most basic and important part of
the spotter training program is to work with the local NWS
staff. Experts from outside will be long gone when severe weather
threatens the community and the spotter training meeting provides an
ideal forum for everyone in the IWS to get to know each other.

In the ideal world, there should be feedback between the
spotters and the people doing the spotter training. No one who has
observed severe storms can say legitimately they have seen it all;
the processes that produce severe local storms are not perfectly
understood and even research scientists and chasers who have been
observing storms for more than 20 years still experience things they
have not seen before. If a spotter is confused by something that he
or she sees, there should be an opportunity to share that with the
NWS spotter trainers, so that the training program can address those
questions, if possible. Although some local efforts to develop this
feedback are underway, there is as yet no organized, system-wide
attempt to promote it.

Assuming that the development of the infrastructure of a volunteer
storm observing network is done and that the training of the spotters
has been carried out, then the system maintains vigilance until a
threatening weather situation arises. Most spotters are volunteers
who have other responsibilities and they simply can't afford to be
idle, waiting for a threatening storm. Thus, the NWS forecasters take
on the task of alerting communities to the immediate threat of severe
local storms, allowing the spotters to go about their normal tasks
until they are needed. A potential deployment of spotters begins with
an Outlook of severe weather, issued by the Storm Prediction Center
(SPC),[7] perhaps as many
as two days prior to the anticipated hazardous weather event. The
Outlook is designed to provide a long-range look at the
possibilities, but it typically covers broad areas with its intent
being to help NWS offices and other components of the IWS be prepared
to provide emergency staffing as threatening weather develops.

As the day of the severe weather threat opens, the local NWS
office can choose to issue an Outlook of their own for that day, with
the idea being to put EMs on the alert to the possible need for
spotter activation. Not all offices provide this sort of product; it
is described in more detail in Moller et al. (1993) and Moller et al.
(1994).

When it becomes apparent that the threat of severe local storms
can be localized, it currently is the duty of the
SPC[8] to issue tornado and
severe thunderstorm watches. Watches are areas of roughly
25,000 km2 (roughly, 10,000 mi2) in which the
threat of severe local storms is thought by the forecasters in the
SPC to be relatively high. The watch is designed to alert both the
public and EMs; the latter need to be alerted in order to give them
time to deploy storm spotters. Following watch issuance, if the
threat materializes to the extent that it either is observed or is
seen on radar to be imminent, the local NWS offices issue warnings
that cover counties or parts of counties.

Still in this ideal world, the spotters are deployed within watch
areas and they report to their EOCs when they see reportable severe
weather events (primarily hail, strong winds, and tornadoes, but also
heavy rainfall and flash floods). In fact, the spotters may have made
the initial observation that resulted in a warning by the NWS.
Alternatively, if the NWS warning was initiated on radar evidence
just prior to the development of hazardous weather, the spotters can
provide feedback to the NWS about the weather they see, via their
EOCs. When spotters observe a severe weather event that is definitely
threatening their community, they report this directly to their EOC,
and the EM makes whatever decisions are necessary to initiate life-
and property-saving actions (such as turning on tornado sirens, if
they exist) in their community. This information is passed on to the
NWS, as well, which may influence forecaster expectations for areas
downstream from the current threatening storms. That is, the reports
can prompt further warnings from the NWS, as long as the storms
remain threatening.

Given the perishable nature of information about severe weather,
there is a premium on getting this information out quickly; media
outlets can choose to break in on their programming to get warnings
on the air as soon as possible. Not all the media choose to approach
this with the same level of commitment, and the nature of the
specific programming often influences this decision. In lieu of
breaking in, television stations often use "crawls" and only break in
during truly critical situations. It is rare when advertising
segments of a broadcast are interrupted to disseminate warning
information.

A recent development is the popularity of cable and direct
satellite feeds of television programming. It is possible to have the
local cable company provide warning "crawls" if the community has
requested that service in their contract with the cable company. For
direct satellite feeds, especially widespread in rural areas, it is
difficult to envision how that might carry local weather warning
information.

Another dissemination medium is via the so-called NOAA Weather
Radio (NWR), which is programmed directly by the NWS. The "reach" of
NWR is sharply limited by the number of transmitters, since the
broadcasts reach only to locations within the transmitter's line of
sight. There have been some efforts to upgrade this service in recent
years, notably after the killer tornadoes in Alabama on 28 March
1994, by increasing the number of transmitters. Although NWR is
broadcast freely, a special radio must be purchased to receive it, as
it does not use the regular AM/FM radio broadcast bands.

There also is a National Warning System (NAWAS) that connects NWS
offices with other Federal and State agencies around the country.
NAWAS is a party line-type telephone system that exists within the
Federal Emergency Management Agency (FEMA). There are ten regional
circuits that can be bridged to form a nationwide capability, if
needed. Its main role is to facilitate coordination in emergencies
and has no "routine" traffic. NAWAS initially was developed as a
response to requirements of the Federal Civil Defense Act of 1950, to
provide warnings of an imminent military attack on the nation, but
has never been used for that purpose.

Considerable communication among spotters, EMs, and the NWS is
done via amateur radio. This normally falls under the aegis of
SKYWARN, which attempts to integrate various amateur radio groups as
well as other components of the IWS. To some extent, telephones still
carry some of the burden for disseminating hazardous weather
information, especially in rural areas.

It has been shown that a significant barrier to getting people to
take action is when the information about warnings that reaches them
includes conflicting guidance. Thus, the NWS generally is designated
to be the primary decision-maker about the need for warnings. This
policy is not followed uniformly and differences of opinion between
the media and the local NWS offices about this issue, or about
interpretation of weather data, can be a problem in the smooth
operation of an IWS. Generally speaking, however, in most locations,
the NWS is recognized as the primary source for severe weather
warnings.

The real world of hazardous weather is sometimes rather far from
ideal. The sequence of forecast products is not always the simple,
somewhat linear process we have just described. Sometimes tornadoes
occur in severe thunderstorm watches. Sometimes severe weather
warnings precede the issuance of watches. Sometimes the
Outlooks need to be amended when unanticipated severe local storms
develop. Sometimes local EMs get panicky and trigger sirens in
situations that do not warrant such actions. Not only is the
meteorological side of the IWS filled with uncertainty, but the
non-meteorological component in an IWS operates at a level short of
perfection.

It is important not to engage in "finger-pointing" exercises when
things in an IWS go wrong. Although it is undoubtedly appropriate to
assess the performance of all the components within an IWS after a
severe weather event, all components in an IWS need to accept that
they are responsible collectively for its performance. When
things go wrong, the important thing to do is to try to fix those
flaws to whatever extent it is possible, rather than to spend time
trying to establish who is to blame. If integration of the components
is an agreed-upon goal, it seems pointless and particularly
counterproductive to spend time trying to blame someone, which can
only create ill-will and engender defensive reactions that are a
barrier to effective integration.

4. Discussion and conclusions

The historical record of tornado fatalities (Fig. 1) might be used
to infer that much of the decrease in fatalities can be attributed to
simple public awareness, and that the effect of public forecasting
service programs does not appear. After all, the downward trend began
after the famous Tri-State tornado of 1925, long before any public
tornado forecasting
began.[9] However, we
believe this would be a misreading of that record. It is impossible
to know what that record might look like had we not instituted
public tornado forecasting, but it is plausible to suggest that the
trend shown could have leveled off at a higher fatality rate than at
present. It seems likely that maintaining that downward trend
must be attributable to some extent to programs like the development
of spotter programs, the inception of public tornado forecasting, and
the public awareness efforts that have been undertaken by the members
of the IWS (i.e., the NWS, the media, schools, etc.). Thus, we
believe that what has been important has been the efforts to continue
to build public awareness.

Fig. 5. Trends in the ratio of the damage to the fatalities, for
selected tornado events in the period from 1880-1995. Events were
selected by a procedure described in the text . The abscissa is the
number of days from 01 January 1904 and the ordinate is the ratio of
the damage to the number of fatalities. The solid black dots are the
individual events, the dotted line is the fitted regression line for
events during the period preceding 1954, the dashed line is the
regression line for events during the period from 1954 to
1995.

In support of this contention,
Fig. 5 shows the apparent
impact of the inauguration of public tornado forecasts and the
ensuing program of watches and warnings, combined with public
education and disaster planning. The trend of the ratio of dollar
damage to fatalities changes abruptly in the period following the
inception of public tornado forecasting. The rapid, organized
development of an infrastructure for dealing with tornadoes also
begins with public tornado forecasting in 1952. The major tornado
events shown in Fig. 5 were selected by first finding all tornadoes
causing 46 or more fatalities, then finding all tornadoes that
produced at least $50 000 worth of damage (in inflation-adjusted 1997
dollars).[10] After
combining these and eliminating duplicates, each tornado's "impact"
was estimated by combining its inflation-adjusted damage with a
figure representing each fatality as equivalent to $8
million.[11] The set of
events was ranked according to this measure and the number of events
selected was truncated at the arbitrary figure of 109 tornadoes out
of this ranked listing. In the figure, the tornado at Flint, Michigan
on 8 June 1953 has been chosen somewhat arbitrarily as the separator
between the two regression lines, since it is the last single tornado
to cause 100 or more fatalities in the United States. The trend lines
are simply regression lines fit to the data, showing the apparent
discontinuity that coincides roughly with the inauguration of public
tornado forecasting.

We have estimated that if the trend in period leading up to and
including the Flint event had remained unchanged, then more than 13
000 additional fatalities might have occurred with the events shown
in the figure. For example, the Wichita Falls, Texas, tornado of 10
April 1979 potentially could have killed 630 persons instead of the
actual 45 fatalities, if fatality rates associated with that amount
of damage had not changed around 1953. This value is only
speculative, of course, and should not be taken too literally.
However, a rough estimate on the order of 10 000 lives spared as a
result of the steps taken in the wake of the pioneering efforts of
Fawbush and Miller in 1948 may not be unreasonable.

The Saragosa tornado of 22 May 1987 is indicated on the figure,
even though it is not included in the regression because it failed to
meet the aforementioned criteria (the number of fatalities was too
low to qualify). In the case of this event, a violent tornado struck
a poor, rural community which had virtually no preparedness program,
in part because it was unincorporated. In spite of excellent NWS
warnings (triggered in part by timely and accurate spotter reports)
in advance of the tornado (see NWS 1988), the damage/fatalities ratio
seems to resemble an event from the earlier era. If some component of
the IWS breaks down, as when events are poorly forecast (as some
events inevitably will be), dissemination is inadequate, or when
community preparedness is poor, then the results can be comparable to
the era before the inception of public tornado forecasting.

It is likely that the downward trends in casualties we have shown
must begin to level off at some point. Tornadoes are virtually
certain to cause some fatalities, no matter what preparations
are made and no matter how accurately we can forecast them. There can
be little doubt that advances in science and technology have helped
maintain the downward trend in fatalities, Moreover, the increasing
dispersion of the slowly growing national population is perhaps
increasing the population at risk, on the whole.

However, storm spotting is going to be an important component of
an integrated warning system in any foreseeable future. The radar
horizon problem alone will limit the ranges at which tornadoes can be
detected by any current radar, for instance. Spotters can help
compensate for this physical limitation associated with any radar. As
we have tried to show, the integrated warning system, whatever its
imperfections, has been successful in reducing tornado casualties.
Small, relatively weak events almost certainly will continue to evade
detection at times. Even tornadoes of modest intensity can result in
casualties under some circumstances. Large, violent events are likely
to produce at least some casualties when they strike populated areas,
no matter how accurate and effective the watches and warnings become.

Increasingly, tornado fatalities are related to bad luck, where
actions that normally would suffice to save lives are not sufficient
(as in the Jarrell, Texas event of 27 May
1997[12]), or where
life-saving actions are precluded by circumstances. Moreover, there
almost certainly will be some isolated events that will slip by
undetected and create casualties, such as the tornado near
Gainesville, GA on 27 March 1998. The current low average annual
death toll certainly is no accident, but as the preliminary casualty
figures already in for 1998 show, the reduced fatality rates should
not be used as an argument that the tornado problem has been
"solved." The year 1998 has seen more than 130 fatalities, which by
recent standards is a very large death toll. To some extent, this has
been associated with bad luck (strong and violent tornadoes hitting
communities with marginal construction, such as mobile home parks,
often at night) but the year could have been worse: as noted, no
major population center has been hit directly by a violent tornado.
Failing to acknowledge the continuing threat from tornadoes could
make us victims of our own success; our society remains vulnerable to
tornadoes, as the annual damage figures and the occasional events of
bad luck show. Maintaining a low fatality rate will not be possible
if commitments to all the components of an IWS are not maintained.
Clearly, further reductions in the casualty rate will require
even greater investments than at present.

It is not difficult to imagine situations that could result in
large fatality totals from a single event in the future. For example,
imagine a violent tornado hitting a crowded sports facility during a
sporting event, or a packed amusement park on a Saturday afternoon (a
situation narrowly missed on 13 June 1998 in Oklahoma City, OK), or a
tornado following a path down gridlocked intracity freeways during
rush hour. No matter how effective the watches and warnings are in
such a case, it is likely that major casualty figures would result.
The record shows a tendency for considerable interannual variability
about the overall trend owing to both good and bad luck. Recently,
the nation has been relatively fortunate; no major population centers
(on the order of St. Louis, Dallas, Atlanta, or Chicago) have been
hit hard in the last 30 years. For instance, if the devastating
tornado on 8 April 1998 had hit Birmingham, AL directly, the casualty
figures could have been substantially higher than they were. The
tornado that hit Nasheville, TN on 16 April 1998 was not a violent
one. We can't expect such luck to continue indefinitely; it is not a
matter of if a population center is struck hard, it is only a
matter of when one will be struck.

We believe there is no choice, therefore, but to maintain
vigilance and continue to put resources toward trying to avert such
disasters to the best of our collective ability. The public has come
to expect public weather services to provide timely, accurate
forecasts of such events and may have an exaggerated expectation of
our ability to do so. Moreover, dissemination of warnings continues
to be a weak link in an IWS. For example, in spite of excellent
watches and warnings during the recent Florida outbreak of tornadoes
on 22-23 February 1998, the 42 fatalities in this outbreak illustrate
several potential problems: the difficulty of tornadoes late at
night, poor public preparedness, large mobile home and RV parks
offering virtually no shelter from tornadoes, etc. The fatality trend
can be driven lower than it is now, but it will take considerable
additional effort and spotters need to be part of that effort.

Further, public awareness should include public acceptance of at
least some part of the responsibility for their own safety. The
downward trend after 1925 suggests that at the time, the acceptance
of this responsibility was reasonably well understood. For instance,
tornado cellars for home in rural areas once were widespread; they
are increasingly rare today. Currently, many people believe that it
is mainly the public weather services that bear the lion's share of
the responsibility for public safety in the event of severe weather.
This attitude needs to be revised. By no means do we want to diminish
the importance of the NWS in an integrated warning system, but for
the system to work properly, all its members must take on
their share of the responsibility. There is not likely ever to be a
time when tornadoes can be forecast with pinpoint accuracy in space
and time, and it is quite likely that important events will be
missed, even as we are improving our ability to provide accurate
watches and warnings. The state of meteorological science with
respect to tornadoes has improved greatly but is still far from a
level of understanding that could prevent all false alarms and
failures to detect. If the public is to be spared as many casualties
as possible, part of our message must be to encourage the users of
hazardous weather information to develop plans for how to deal with
the occasional events that are poorly anticipated, and how to account
for the finite capabilities of weather forecasters to deal with
tornadoes. Spotters are now and will continue to be an important part
of those plans.

Tornadoes are rare events, and it is possible to spend an entire
lifetime, even in the center of what is known colloquially as
"Tornado Alley," and never even see a tornado, much less experience
one. Further, the average annual fatality count from tornadoes is no
longer at a level where it regularly attracts much attention; only if
the bad luck of 1998 continues is there much hope of continuing
publicity about tornado vulnerability. Apathy and indifference can
lead to disasters, especially on the margins of the tornado-prone
parts of the United States. Many citizens in such locations may be
unaware of the possibility of significant tornadoes, in spite of the
historical record showing clearly that strong and violent tornadoes
are possible anywhere over at least the eastern two-thirds of
the nation. Complacency means an increased risk of disasters in those
places where public perceptions are falsely on the side of "It can't
happen here." Spotting networks and preparedness efforts (including
public education and participation in severe weather awareness
programs) can pay off in reducing risks, but it takes considerable
effort to create and maintain vigilant spotter programs in locations
where the public has a false sense of security about tornado risks.
The spotters themselves may lose interest waiting to see what is,
after all, a rare event.

The history of tornadoes shows pretty clearly that actions taken
in preparation for tornadoes are often deferred until after a
disaster has occurred. Our review of the history of the development
of spotters suggests that the IWS has been shaped primarily by major
events that produced numerous fatalities, like the Tri-State Tornado,
the so-called "Woodward" tornado of 9 April 1947, the disasters of
1953 (i.e., Waco, Texas on 11 May, Flint, Michigan on 8 June, and
Worcester, Massachusetts on 9 June), the 1965 Palm Sunday outbreak,
the "Super Outbreak" of 1974, and so on. In effect, it seems that
major disasters are needed for any progress to be made. Experience
suggests that the memory of such disasters fades from the collective
consciousness rather faster than it should. We believe that resource
expenditures must be continued to maintain the sense of
vigilance created by such events; otherwise, the tragic consequences
will be repeated at another time and/or another place. The lessons
learned will have to be relearned after new and unnecessary
fatalities. Although most citizens will never experience a tornado,
it is possible to control the fatality count with proper
preparations, disaster plans, and an integrated warning system.

Acknowledgments. Tom Grazulis supplied part of the data used in this
study, as well as some helpful discussions. Allen Pearson, Herb Lieb,
Rainer Dombrowsky, Mike Redman, Gary Woodall, Mike Mogil, Bob
Carnahan, Jim Purpura, and Dan Purcell all provided input that
contributed substantially to the factual content of historical
aspects in this review. We appreciate thoughtful and beneficial
reviews from Don Burgess and an anonymous referee.